Optical recording medium

ABSTRACT

An optical recording medium has a user data area and a lead-out area each having grooves and lands formed thereon. Wobbles are formed on at least one lateral surface of the grooves of the user data area and the lead-out area, and configured such that wobble characteristics are made different between the user data area and the lead-out area. Different types of the wobbles are formed on the grooves of either the user data area or the lead-out area, thereby preventing an optical pickup that performs recording/reproducing, from deviating from the user data area. Also, in a multi-layer optical recording medium, a whole area of a recording layer is configured to have the same condition, thereby preventing deterioration in reproducing and/or recording due to a difference in light power transmittance of another recording layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Korean Application No.2002-14095, filed Mar. 15, 2002, in the Korean Industrial PropertyOffice, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an optical recording medium, andmore particularly, to an optical recording medium having wobbles formedon at least one lateral surface of grooves of a user data area andgrooves of a lead-out area, and configured such that wobblecharacteristics between the user data area and the lead-out area aredifferent from each other.

[0004] 2. Description of the Related Art

[0005] In general, optical recording media are widely employed asinformation recording media for an optical pickup devicerecording/reproducing information on/from the optical recording media.The optical recording media are classified into read-only-memory (ROM)compact discs (CDs) and digital versatile discs (DVDs) according toinformation recording capacity. Further, a DVD disc which information iswritten on, erased, and read from, can be sub-divided into a digitalversatile disc-random access memory (DVD-RAM) disc and a digitalversatile disc-rewritable (DVD-RW) disc.

[0006] In a DVD-RAM or DVD-RW disc shown in FIG. 1, there is a lead-inarea 10 in which read only data, such as a disc size, the number oftrack layers on a readable plane, or illegal copy preventinginformation, is recorded, a user data area 20 in which user data can berepeatedly read and/or written, and a lead-out area 30 in which otherdisc-related information is recorded.

[0007] As indicated by a portion “C” of FIG. 1, there are grooves 23 andlands 25 alternatively formed in the user data area 20 so as for theoptical pickup device to perform recording and/or reproducinginformation marks 27 along a predetermined track. In FIG. 1, referencenumeral 40 denotes a reproduction beam. From enlarged portions A and Bof the lead-in area 10 and the lead-out area 30, it is confirmed thatphysical pits 15, which are the read only data, are formed thereon.Here, the lead-out area 30 is used for performing various functions. Forexample, the lead-out area 30 guards an optical pickup not to deviatefrom the user data area 20 while the optical pickup performs arecording/reproducing process.

[0008] In particular, as shown in FIG. 2, in a dual-layer opticalrecording medium having a first recording layer L0 and a secondrecording layer L1 of opposite track paths, the lead-out area 30 allowsthe optical pickup device to keep performing tracking duringinterlayer-jumping from an outermost circumference of the firstrecording layer L0 to another outermost circumference of the secondlayer L1 without deviating from the track paths. The opposite trackpaths are sequentially addressed from an inner circumference of thefirst recording layer L0 to an outer circumference thereof, and thenfrom an outer circumference of the second recording layer L1 to an innercircumference thereof.

[0009] In a dual-layer ROM disc, an area serving as the lead-out area 30varies according to a reproduction method of the second recording layer12. In the dual-layer ROM disc having the opposite track paths, a middlearea is separately provided at each of the outer circumferences of thefirst and second recording layers L0 and 11. However, in a case of arewritable optical recording medium, both pits and grooves can be used.Therefore, in a case of dual layer rewritable optical recording media,recording power is affected by a physical geometry of the firstrecording layer L0 during recording data. In other words, when recordingis performed on the second recording layer L1, a recording light beampasses through the first recording layer L0, resulting in a differencein transmittance between pit portions and groove portions.

[0010] Light power was measured for an optical recording medium at amirror area, a pit area, a groove area and a groove area with marks tosimulate the light power depending on a difference in the transmittanceaccording to various conditions of the first recording layer L0, asshown in FIGS. 3A through 3D. Here, the number of tracks trapped by alaser beam transmitted through a lens was taken into consideration.

[0011] Tables 1 and 2 list input parameters and items forexperimentation. In Table 1, Rc represents reflectivity of acrystallized portion of a recording layer and Ra represents thereflectivity of an amorphous portion of the recording layer. TABLE 1Parameter Condition Wavelength (nm) 400 Numerical Aperture (NA)0.65/0.85 Minimum mark length (μm) 0.275/0.194 Modulation EFM+(Eight-to-Fourteen Modulation-plus) Track pitch (TP) (μm) 0.30, 0.34,0.38 Reflectivity (%) Rc = 25, Ra = 5

[0012] TABLE 2 Item Factor Example Dual recording Structure of firstrecording Mirror, pits, grooves, layer layer grooves with marks. High NANumber of tracks trapped by 85 for 0.65 of NA laser beam 160 for 0.85 ofNA Incident angle of beam 40.5° for 0.65 of NA 58.2° for 0.85 of NA

[0013]FIG. 4 is a graph showing measurement results of the light powerdepending on the transmittance for the cases shown in FIGS. 3A, 3B, 3Cand 3D. With reference to FIG. 4, according to a simulation result, adecrease in the light power is smallest in the mirror portion (graphline with solid squares), and the light power gradually decreases morein the order of a pit portion (graph line with solid diamonds), a grooveportion (graph line with solid triangles) and a groove mark portion(graph line with solid circles). Therefore, as shown in FIG. 4, in thecase of a dual layer disc, the transmittance varies according to thephysical geometry of the first recording layer L0 while a rewritableoptical recording medium can further affect the recording power duringrecording data. Accordingly, it is necessary to unify the physicalgeometry of the recording layer and to newly define the lead-out area orthe middle area.

SUMMARY OF THE INVENTION

[0014] To solve the above and/or other problems, it is an aspect of thepresent invention to provide an optical recording medium having alead-out area configured to prevent a pickup from deviating from a userdata area during recording and/or reproducing data without affecting arecording power of the pickup.

[0015] Additional aspects and advantages of the invention will be setforth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of theinvention.

[0016] Accordingly, to achieve the above and/or other aspects of theinvention, an optical recording medium includes a user data area and alead-out area each having grooves and lands formed thereon, and wobblesformed on at least one lateral surface of each of the grooves. Thewobbles of the lead-out area have different characteristics from thoseof the user data area.

[0017] It is possible that the wobbles of the lead-out area are formedby modulating at least one feature of a frequency, a period (length), anamplitude and a phase of the wobbles of the user data area.

[0018] It is possible that at least one modulation method among afrequency modulation, a period (length) modulation, an amplitudemodulation, a phase modulation, an HWM modulation and a combinedmodulation of wobble and non-wobble portions, is employed to form thewobbles of the user data area, and a modulation method different fromthat employed to form the wobbles of the user data area is employed toform the wobbles of the lead-out area, so that an optical pickup may notdeviate from the user data area during recording and/or reproducingdata.

[0019] It is possible that the wobbles may include addressinginformation or reference time information in a form of a phase lockedloop (PLL).

[0020] It is possible that in addition to the different wobbles in theuser data area and the lead out area, synchronization patterns ofsignals read from the grooves of the user data area and the lead-outarea are different.

[0021] It is possible that in addition to the different wobbles in theuser data area and the lead-out area, predetermined recording patternsare recorded on the outermost circumference of the optical recordingmedium to prevent an optical pickup from deviating from the user dataarea during recording and/or reproduction of data.

[0022] In the optical recording medium, two or more recording layers maybe provided for multi-layer recording.

[0023] It is possible that in a case of multi-layer recording media, thetwo or more recording layers have different recording patterns in theirlead-out areas.

[0024] It is possible that in the multi-layer recording media, the twoor more recording layers have different synchronization patterns intheir lead-out areas.

[0025] It is possible that in the multi-layer recording media, thelead-out area has a width of two or more times a maximum allowance ofdisc eccentricity.

[0026] In another aspect of the present invention, an optical recordingmedium includes a user data area and a lead-out area, in whichpredetermined recording patterns are recorded on an outermostcircumference of the optical recording medium to prevent an opticalpickup from deviating from the user data area during recording and/orreproducing data.

[0027] According to another aspect of the present invention, an opticalrecording medium includes a user data area and a lead-out area eachhaving grooves and lands formed thereon, and different types ofsynchronization patterns are used in the lead-out area and the user dataarea.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] These and/or other aspects and advantages of the invention willbecome apparent and more readily appreciated from the followingdescription of the preferred embodiments, taken in conjunction with theaccompanying drawings of which:

[0029]FIG. 1 shows a schematic diagram and an enlarged view of aconventional optical recording medium;

[0030]FIG. 2 is a partially cross-sectional view illustrating aconventional dual-layer optical recording medium;

[0031]FIGS. 3A through 3D illustrate various portions of theconventional optical recording medium shown in FIG. 1;

[0032]FIG. 4 illustrates an experimental result of light power invarious cases of the conventional optical recording medium shown inFIGS. 3A through 3D; and

[0033]FIG. 5 is a schematic view of and an enlarged view an opticalrecording medium according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Hereinafter, example embodiments of the present invention will bedescribed in detail with reference to the attached drawings where likereference numerals refer to the like elements throughout. Theembodiments are described below to explain the present invention byreferring to the figures and to more completely explain the presentinvention to anyone skilled in the art. The present invention is notrestricted to the following embodiments, and many variations arepossible within the spirit and scope of the present invention, the scopeof which is defined in the claims and their equivalents.

[0035] Referring to FIG. 5, an optical recording medium according to anembodiment of the present invention includes a lead-in area 100, a userdata area 120 and a lead-out area 130, each area having grooves 123 andlands 125 formed thereon. Wobbles 105 and 135 are formed on at least onelateral surface of each of grooves 123 and lands 125 in the user dataarea 120 and the lead-out area 130, respectively. Here, a portion “E” ofthe user data area 120 and a portion “D” of the lead-out area 130 areenlarged and shown in FIG. 5. Reference numeral 110 denotes a laserbeam.

[0036] As described above, the lead-out area 130 has a guard functionthat prevents an optical pickup (not shown) from deviating from the userdata area during recording and/or reproducing data, and in a case of adual-layer disc, the lead-out area can be used for controlling theoptical pickup to keep/maintain tracking while interlayer-jumping froman outermost circumference of the optical recording medium.

[0037] In the optical recording medium, to provide the guard function,the wobbles 135 different from the wobbles 105 in the user data area 120are formed in an area beyond a predetermined radius of the opticalrecording medium (for example, a] the lead-out area). In other words, atleast one kind of features including periods (lengths), frequencies,amplitudes and phases of the wobbles 105 and 135 are modulated in theuser data area 120 and the lead-out area 130. Hereinafter, “period” isreferred to as “length.” In addition, a combination modulation method ofa wobble portion and a non-wobble portion having a predetermined length,or an HWM (Harmonic Wave Modulation) method may be employed. The phasemodulation is exemplified by QPSK (Quadrature Phase Shift Keying) inwhich phases of a wobble signal is shifted by 90 degrees. The frequencymodulation is exemplified by MSK (Minimum Shift Keying) in which onlyfrequencies of some sections of continuous wobbles vary. The HWM methodis exemplified by a serration modulation.

[0038] Among the above-stated modulation methods, the same modulationmethod may be employed to the user data area 120 and the lead-out area130. For example, the wobbles 135 of the lead-out area 130 can be formedby modulating at least one feature of the frequency, the period(length), the amplitude and the phase of the wobbles 105 of the userdata area 120 as follows. In a case of modulating the frequencies of thewobbles 105 and 135, the wobble 135 of the lead-out area 130 may beformed to have a frequency of n times (n is a real number) a basicfrequency of the wobble 105 of the user data area 120. For example, toserve as a guard, the lead-out area 130 may be configured such that thewobble 135 has a frequency of 2 times that of the user data area 120.

[0039] Further, in a case of modulating a wobble period (length) T, thewobble 105 of the user data area 120 and the wobble 135 of the lead-outarea 130 can, for example, have periods (lengths) 200T and 100T,respectively, so that the lead-out area 130 can be discriminated fromthe user data area 120. Here, after completion of manufacturing a disc,00h as pattern data may be recorded in the lead-out area 130.Accordingly, the 00h pattern data is read out by a channel 1 (Ch1)during a recording/reproducing process, and the wobble frequency and/orperiod can be read out by a channel 2 (Ch2), thereby allowing doublediscrimination of the lead-out area 130 from the user data area 120.

[0040] On the other hand, different modulation methods may be employedto the wobbles 105 and 135 of the user data area 120 and the lead-outarea 130, which will now be described in more detail.

[0041] First, at least one modulation method among the frequencymodulation, period (length) modulation, amplitude modulation, phasemodulation, HWM modulation and combined modulation methods of wobble andnon-wobble portions, may be employed to the wobbles 105 of the user dataarea 120, and a modulation method different from that employed to thewobbles 105 of the user data area 120 may be employed to the wobbles 135of the lead-out area 130. Hereinafter, “period modulation” is referredto as “length modulation.” For example, the wobbles 105 of the user dataarea 120 can be formed by the frequency modulation method while thewobbles 135 of the lead-out area 130 can be formed by the phasemodulation method.

[0042] Second, a mixed modulation method of mixing (combining) two ormore modulation methods among the frequency modulation, periodmodulation, amplitude modulation, phase modulation, HWM modulation andcombined modulation methods of the wobble and non-wobble portions, maybe employed to the wobbles 105 of the user data area 120, and at leastone single modulation method among the frequency modulation, periodmodulation, amplitude modulation, phase modulation, HWM modulation andcombined modulation methods of the wobble and non-wobble portions, maybe employed to the wobbles 135 of the lead-out area 130. For example,the wobbles 105 of the user data area 120 can be formed by a mixedmodulation method of combining the HWM method and the phase modulationmethod while the wobbles 135 of the lead-out area 130 can be formed bythe phase modulation method.

[0043] Third, at least one single modulation method may be employed tothe wobbles 105 of the user data area 120, and the mixed modulationmethod may be employed to the wobbles 135 of the lead-out area 130,which is opposite to the above-described second case. For example, thewobbles 105 of the user data area 120 can be formed by the frequencymodulation method while the wobbles 135 of the lead-out area 130 can beformed by the mixed modulation method of the frequency modulation, e.g.,MSK, method and the amplitude modulation method.

[0044] Fourth, the mixed modulation method of two or more modulationmethods may be employed to the wobbles 105 of the user data area 120,and another mixed modulation method different from that employed to thewobbles 105 of the user data area 120 may be employed to the wobbles 135of the lead-out area 130.

[0045] As described above, different wobble modulation methods areemployed to the user data area 120 and the lead-out area 130, therebyproviding the guard function to the lead-out area 130. In other words,at least one modulation method among the frequency modulation, periodmodulation, amplitude modulation, phase modulation, HWM modulation andcombined modulation methods of the wobble and non-wobble portions, maybe employed to the wobbles 105 of the user data area 120, and anothermodulation method different from that employed to the wobbles 105 of theuser data area 120 may be employed to the wobbles 135 of the lead-outarea 130, thereby achieving the guard function.

[0046] In an optical medium according to another embodiment of thepresent invention, when formatting the optical medium, a predeterminedrecording pattern can be recorded in the lead-out area 130, therebydiscriminating the lead-out area 130 from the user data area 120.

[0047] The predetermined recording pattern may be, for example, arecording pattern used in the user data area 120. That is to say, amongrecording patterns used in the user data area 120, the predeterminedrecording pattern, for example, a 00h pattern, can be repeatedlyrecorded in the lead-out area 130, thereby allowing the optical pickupto recognize the lead-out area 130.

[0048] Alternatively, the recording pattern not used in the user dataarea 120 is recorded in the lead-out area 130, thereby allowing theoptical pickup to recognize the lead-out area 130. For example, the 00hpattern is recorded in the user data area 120 and an FFh pattern asanother pattern is recorded in the lead-out area 130. Therefore, in thiscase, the recording patterns recorded on the lead-out area 130 aredifferent from those used in the user data area 120. Here, the 00h andFFh patterns are recording patterns based on a hexadecimal system.

[0049] According to another embodiment of the present invention, theoptical medium includes the user data area 120 and the lead-out area130, each having the grooves 123 and the lands 125. Different types ofsynchronization patterns (to be abbreviated as “sync patterns”hereinafter) are used in the user data area 120 and the lead-out area130. Thus, the lead-out area 130 is discriminated from the user dataarea 120 by recognizing the sync patterns, thereby preventing theoptical pickup from deviating from the user data area 120 during therecording/reproducing process.

[0050] Here, a width of the lead-out area 130 in a radial direction maybe determined to be two or more times the maximum allowance of the disceccentricity, and it is possible that the width is 100 μm or greater.

[0051] Also, according to an aspect of the present invention amulti-layer optical recording medium includes two or more recordinglayers as follows. The multi-layer optical recording medium includes theuser data area 120 and the lead-out area 130, each having the grooves123 and the lands 125.

[0052] The wobbles 105 and 135 are formed on at least one lateralsurface of each of the grooves 123 and the lands 125. The wobbles 105and 135 may include addressing information or reference timeinformation, e.g., phase locked loop (PLL). To prevent the opticalpickup from deviating from the user data area 120, the wobbles 105 and135 formed in the user data area 120 and the lead-out area 130,respectively, may be modulated into different types of wobbles.

[0053] Further, in the multi-layer optical recording medium having twoor more recording layers, different recording patterns are formed oneach lead-out area 130 of the respective recording layers, therebydiscriminating the respective recording layers. For example, in the adual-layer optical recording medium, the 00h pattern may be recorded onthe lead-out area 130 of a first recording layer, and the FFh patternmay be recorded on the lead-out area 130 of a second recording layer. Bydoing so, the recording patterns are read out by a channel 1 (Ch1) andwobble signals based on the wobble modulation method are read out by achannel 2 (Ch2), during recording and/or reproducing on/from themulti-layer optical recording medium.

[0054] Further, to maintain tracking during interlayer-jumping, thewidth of the lead-out area 130 may be determined to be two or more timesthe maximum allowance of the disc eccentricity. If the disc eccentricityoccurring according to injection in manufacturing a disc isapproximately 50 μm, the width of the lead-out area 130 is determined tobe 100 μm or greater.

[0055] According to another embodiment of the present invention, todiscriminate the respective recording layers in the multi-layer opticalrecording medium having the two or more recording layers, different syncpatterns may be used for each recording layer in the lead-out area 130.By using the wobbles according to the embodiments of the presentinvention, a whole area of each recording layer can be configured tohave the same condition, thereby providing a uniform transmittance ofthe respective recording layers.

[0056] In the multi-layer optical recording medium, the whole area,including the user data area 120 and the lead-out area 130, is formedinto grooves, so that the whole area of the first recording layer isconfigured to have the same condition, thereby preventing deteriorationin the reproducing and/or recording process due to a difference in lightpower transmittance of the first recording layer.

[0057] Also, different modulation methods are employed to form thewobbles 105 and 135 of the user data area 120 and the lead-out area 130,respectively, or synchronization patterns of signals read from the userdata area 120 and the lead-out area 130 are made different, therebyproviding the guard function to prevent the optical pickup fromdeviating from the user data area 120 during recording and/orreproducing of data.

[0058] While this invention has been particularly shown and describedwith reference to example embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the spirit and scope of theinvention as defined by the appended claims and their equivalents.

What is claimed is:
 1. An optical recording medium comprising: a userdata area and a lead-out area each having grooves and lands formedthereon, wherein wobbles are formed on at least one lateral surface ofeach of the grooves, and the wobbles of the lead-out area have differentcharacteristics from those of the user data area.
 2. The opticalrecording medium according to claim 1, wherein the wobbles of thelead-out area are formed by modulating at least one feature of afrequency, a period, an amplitude and a phase of the wobbles of the userdata area.
 3. The optical recording medium according to claim 2, whereinthe wobbles of the lead-out area include addressing information orreference time information in a form of a phase locked loop (PLL). 4.The optical recording medium according to claim 2, wherein the user dataarea and the lead-out area comprise: synchronization patterns formed onthe grooves of the user data area and the lead-out area, and thesynchronization pattern of the user data area is different from that ofthe lead-out area.
 5. The optical recording medium according to claim 2,wherein the optical recording medium is readable in an optical pickup,and the wobbles comprise: recording patterns recorded on an outermostcircumference of the optical recording medium to prevent the opticalpickup from deviating from the user data area during recording and/orreproducing data on/from the optical recording medium.
 6. The opticalrecording medium according to claim 1, wherein the grooves comprisewobble and non-wobble portions, the optical recording medium is readablein an optical pickup, at least one modulation method among frequencymodulation, period modulation, amplitude modulation, phase modulation,HWM modulation, and combined modulation methods of the wobble andnon-wobble portions, is employed to the wobbles of the user data area,and another modulation method different from that employed to thewobbles of the user data area is employed to the wobbles of the lead-outarea, so that the optical pickup may not deviate from the user data areaduring recording and/or reproducing data on/from the optical recordingmedium.
 7. The optical recording medium according to claim 6, whereinthe wobbles of the lead-out area comprise: addressing information orreference time information in a form of a phase locked loop (PLL). 8.The optical recording medium according to claim 6, wherein the user dataarea and the lead-out area comprise: synchronization patterns formed onthe grooves of the user data area and the lead-out area, and thesynchronization pattern of the user data area is different from that ofthe lead-out area.
 9. The optical recording medium according to claim 6,wherein the wobbles comprise: recording patterns recorded on anoutermost circumference of the optical recording medium to prevent theoptical pickup from deviating from the user data area during recordingand/or reproducing data.
 10. The optical recording medium according toclaim 1, wherein the wobbles of the lead-out area comprise: addressinginformation or reference time information in a form of a phase lockedloop (PLL).
 11. The optical recording medium according to claim 1,wherein the user data area and the lead-out area comprise:synchronization patterns formed on the grooves of the user data area andthe lead-out area, and the synchronization pattern of the user data areais different from that of the lead-out area.
 12. The optical recordingmedium according to claim 1, wherein the optical recording medium isreadable in an optical pickup, an the wobbles comprise: recordingpatterns recorded on an outermost circumference of the optical recordingmedium to prevent the optical pickup from deviating from the user dataarea during recording and/or reproducing of data on/from the opticalrecording medium.
 13. The optical recording medium according to claim 1,further comprising two or more recording layers for multi-layerrecording.
 14. The optical recording medium according to claim 13,wherein: each recording layer comprises, the user data area and thelead-out area; and the two or more recording layers comprises, differentrecording patterns in respective lead-out areas.
 15. The opticalrecording medium according to claim 14, wherein the lead-out area has awidth of two or more times a maximum allowance of disc eccentricity in aradial direction of the optical recording medium.
 16. The opticalrecording medium according to claim 1, wherein the optical recordingmedium is recordable, and recording is performed on the grooves and/orthe lands.
 17. An optical recording medium readable in an optical pickupcomprising: a user data area; and a lead-out area, wherein recordingpatterns are recorded on an outermost circumference of the lead-out areato prevent the optical pickup from deviating from the user data areaduring recording and/or reproducing data on/from the optical recordingmedium.
 18. The optical recording medium according to claim 17, whereinthe recording patterns are formed by repeatedly recording the samerecording patterns used in the user data area.
 19. The optical recordingmedium according to claim 17, wherein the user data area comprisessecond recording patterns, and the recording patterns are different fromthe second recording patterns used in the user data area.
 20. Theoptical recording medium according to claim 17, wherein the user dataarea and the lead-out area comprise first and second synchronizationpatterns, respectively, and the first and second synchronizationpatterns used in the user data area and the lead-out area are different.21. The optical recording medium according to claim 20, furthercomprising: two or more recording layers for multi-layer recording. 22.The optical recording medium according to claim 21, wherein eachrecording layer comprises the user data area and the lead-out area, andthe two or more recording layers have different recording patterns fromone another.
 23. The optical recording medium according to claim 17,wherein the lead-out area has a width of two or more times a maximumallowance of disc eccentricity in a radial direction of the opticalrecording medium.
 24. The optical recording medium according to claim17, wherein the user data area and the lead-out area comprise:synchronization patterns formed on the grooves of the user data area andthe lead-out area, and the synchronization pattern of the user data areais different from that of the lead-out area.
 25. The optical recordingmedium according to claim 17, further comprising: two or more recordinglayers for multi-layer recording.
 26. The optical recording mediumaccording to claim 25, wherein the two or more recording layerscomprise: different recording patterns from one another.
 27. The opticalrecording medium according to claim 17, wherein the optical recordingmedium is recordable, and recording is performed on the grooves and/orthe lands.
 28. An optical recording medium having a user data area and alead-out area, wherein the user data area and the lead-out area eachhave grooves and lands formed thereon, and different types ofsynchronization patterns are used in the lead-out area and the user dataarea.
 29. An optical recording medium compatible with an optical pickupreading data from the optical recording medium, comprising: a firstrecording layer having a first lead-in area, a first user data area, anda first lead-out area; and a second recording layer having a secondlead-in area, a second user data area, and a second lead-out area,wherein wobbles are formed in the first and second lead-out areas. 30.The optical recording medium according to claim 29, wherein the opticalpickup maintains tracking during interlayer-jumping between the firstand second recording layers using the wobbles of the first and secondlead-out areas.
 31. The optical recording medium according to claim 29,wherein the optical pickup is prevented from deviating from the firstand second lead-out areas during interlayer-jumping between the firstand second recording layers using information corresponding to thewobbles of the first and second lead-out areas.
 32. The opticalrecording medium according to claim 29, wherein the optical pickup isprevented from deviating from the first and second user data areasduring interlayer-jumping between the first and second recording layersusing information corresponding to the wobbles of the first and secondlead-out areas.
 33. The optical recording medium according to claim 29,wherein the first and second lead-out areas of the first and secondrecording layers comprise: grooves and lands.
 34. An optical recordingmedium compatible with an optical pickup reading data from the opticalrecording medium, comprising: a lead-in area; a user data area; and alead-out area, wherein wobbles are formed in the lead-out area.
 35. Theoptical recording medium according to claim 34, wherein the lead-outarea comprises: grooves and lands.
 36. The optical recording mediumaccording to claim 35, wherein the wobbles are formed on a lateralsurface of respective grooves.
 37. The optical recording mediumaccording to claim 35, wherein the lead-out area comprises: recordingpatterns formed on corresponding ones of the grooves.
 38. An opticalrecording medium compatible with an optical pickup reading data from theoptical recording medium, comprising: a first recording layer having afirst lead-in area, a first user data area, and a first lead-out area;and a second recording layer having a second lead-in area, a second userdata area, and a second lead-out area, wherein grooves and lands areformed in the first and second lead-in areas, the first and second userdata areas, and first and second lead-out areas, and wobbles are formedin the first and second lead-out and user data areas to provide auniform transmittance of the first and second layers of the opticalrecording medium.
 39. An optical recording medium compatible with anoptical pickup reading data from the optical recording medium,comprising: a lead-in area; a user data area; and a lead-out area,wherein grooves and lands are formed in the lead-in, user data, andlead-out areas, and wobbles are formed in the lead-out and user dataareas to provide a uniform transmittance of the lead-out and the userdata areas of the optical recording medium.